Can anyone point me in the direction of blurring an image while the rest of it downloads? Its almost as if Facebook is downloading a percentage of the image, then blurs it while the rest is downloading? if that makes sense..? Thanks in advance!
+6
A:
It's most likely because they are using progressive jpegs or similar image formats.
Timo Geusch
2010-06-03 21:16:10
any idea on how to implement the progressive download on the images I am downloading to my app?
Louie
2010-06-03 21:25:52
It's usually an option in advanced photo editing applications when saving a file. In Photoshop, for example, you could open your image, choose "Save As..." (JPG) and then in the "Format Options" section, choose "Progressive", and set the number of scans (3, 4, or 5). Not sure how FB gets just two scans -- probably using some other software.
Cory Larson
2010-06-04 12:25:01
GIMP does it as well, in case you were looking for a free solution :)
Cory Larson
2010-06-04 12:32:35
+3
A:
My guess is that you're downloading a progressive JPG (at one time, would have been an interlaced GIF). PNG also supports an interlaced option, if memory serves.
In any case, Facebook itself isn't doing much other than encoding the pictures using the progressive/interlaced format. Your browser takes care of showing the lower resolution version during the download, then showing the sharper version when the download finishes.
Jerry Coffin
2010-06-03 21:16:50